Category Archives: astronomy

Photo courtesy of Andy Veh. A lunar eclipse is coming up March 23, but don’t get too excited —it won’t be as spectacular as this one from October 2014.

By Andy Veh, for the Redoubt Reporter

The constellation that always catches my eye in March is Leo, its shape quite closely resembling that of a male lion lying leisurely, watching the savannah, looking west, in the direction that it will move toward during the next couple of months. Its right front paw is the bright star Regulus.

While Leo should move across the sky as gingerly as any constellation week after week, it seems to be much speedier than others. What aids this perception is that sunset occurs later and later, about 20 minutes each week. Thus, with it getting darker later every evening, it seems that Leo keeps progressing across the sky faster (because we look at it later when it already has moved farther west).

As a result, I perceive Leo as the harbinger of spring —when it appears in the east, winter’s end will soon be here, and when it reaches the western horizon, flowers are in full bloom and deciduous trees will have regained their leaves.

Leo with Regulus follows the bright stars of winter (perhaps chasing them off). Sirius is low in the south and quite prominent, but even being the brightest star in the sky, as seen from our solar system, it’s no match for the brightness of Jupiter and Venus. Ahead of Sirius are Betelgeuse, Rigel, Pollux, Castor, Capella, Aldebaran and Procyon, all of them appearing above the southern horizon.

Bright stars in the remaining sky are Deneb and Vega in the north and Arcturus and Spica rising in the east in the late evening, the latter close to Mars. The waning third-quarter moon is near Mars on Feb. 29. Saturn is following on their heels with the same third-quarter moon nearby on March 2.

Late in the evening, winter constellations such as Taurus, Pegasus and Andromeda have set already. But others show their glory, such as Orion with its seven bright stars — among them red Betelgeuse and blue Rigel — Auriga with yellow Capella, Gemini with Castor and Pollux, and Procyon and Sirius in Canis Minor and Major, both arching toward the horizon from the Twins.

Lately, I have enjoyed seeing the brightest star, Sirius, above the southern horizon in the evening. Leo, a harbinger of spring, with Regulus in its front paw, appears high in the south. The Big Dipper is now virtually overhead. Blue Vega and Cygnus with Deneb are just above the Little Dipper. Polaris, as always, is 60 degrees above the northern horizon. And in the east, Bootes appears with red Arcturus.

Uranus can still be seen in the evening, but it requires a finder chart (I recommend Googling one). The sun has finally moved in on slow-orbiting Neptune (of course, the sun doesn’t move, Earth’s orbit just gives it that impression), so that the planet is no longer visible until the fall.

Photo courtesy of Susan Mircovich, Kenai Peninsula College. Venus emerging from its lunar occultation, pictured in front of Pioneer Peak along the Knik River on Dec. 7.

By Andy Veh, for the Redoubt Reporter

The starry sky is at its best with the most prominent stars high in the south — Blue Rigel and red Betelgeuse in Orion, Sirius beneath it, Procyon to its left, Pollux and Castor higher up, Capella almost in the zenith and Aldebaran and the Pleiades completing the splendor.

The Big Dipper starts out close on the northern horizon but Cassiopeia, Perseus and Andromeda are close to the zenith. In the west, Cygnus and Pegasus are about to set, while bright Vega, being circumpolar in Alaska, stays close to the horizon. Leo’s Regulus rises in the evening, trailing Gemini and Cancer low in the east.

Several planets are visible throughout January.

Uranus and Neptune can still be seen in the evening but they require finder charts. (I recommend Googling them.)

You can’t miss bright Jupiter as it rises in the east in the late evening, moving through the south during the night and setting in the west when school starts in the morning. This winter it appears between Leo and Virgo, halfway between these constellations’ brightest stars, Regulus and Spica.

Jupiter appears to be stationary this month. While it orbits on a nice, slightly elliptical orbit around our sun, we on Earth are starting to overtake it because we move along on a smaller, but still nice and slightly elliptical, orbit. So from our vantage point, Jupiter seems to slow down, come to a stop (on Jan. 8) and move backward — retrograde (which is an optical illusion) — through early May. When we finally pass the giant planet, it seems to stop again and regain its regular motion. The gibbous moon is near Jupiter on Jan. 27.

Mars rises longer after midnight but can be glimpsed before and during dawn. Follow the line of Regulus to the right, Jupiter in the middle and Spica to the left and you will find reddish Mars just east of Spica. Farther east are Saturn and Venus, but those two are close to the southern horizon before sunrise, which is also the only time they can be seen. The last quarter moon will be near Mars on Jan. 31.

Earth was at perihelion — its closest approach to the sun — on Jan. 2 (91.4 million miles) but only by 3 percent closer compared to its aphelion — its farthest distance from the sun — on July 4 (94.5 million miles). That means that about 6 percent more of the sun’s energy reaches Earth.

The winter constellations are rising in the east and gaining altitude throughout the next two months. Orion is easy to spot with its seven bright stars — among them, red Betelgeuse is the 10th-brightest star we see from Earth, and blue Rigel is the seventh-brightest — and its stellar nursery, the Orion Nebula. Also look for Taurus with red Aldebaran (14th-brightest) and its prominent star cluster, the Pleiades; Auriga with yellow Capella (sixth-brightest); and Gemini with the twin stars Castor (23rd-brightest) and Pollux (17th brightest).

The head of Canis Major has the brightest star (aside from the sun) that we can see from Earth — Sirius, as well as Procyon (eighth-brightest). Look for Regulus (21th-brightest) in Leo very late in the evening.

Because this region of the sky hosts seven of the 20 brightest stars (again, not counting our sun) as seen from Earth, and because it contains quite a few easily recognizable constellations, it is my favorite region of the sky.

High in the south is the Great Square of Pegasus in the shape of a diamond. Above it, close to the zenith, is Cassiopeia. Getting close to the western horizon — but never completely setting in Alaska — are the three stars that make up the summer triangle, Deneb (20th-brightest) in Cygnus, Vega (fifth-brightest) in Lyra, and Altair (13th-brightest) in Aquila. Aquila does set, but just barely for a few hours.

In the north are Ursa Major’s Big Dipper and Ursa Minor’s Little Dipper, which is always close to 60 degrees, our latitude on the Kenai.

Keep looking for Neptune and Uranus in the evening. They appear quite low now in the south in Aquarius and Pisces (both are below Pegasus). A good finder chart is needed, though. Try here. The first-quarter moon joins Neptune on Dec. 16, and then Uranus on Dec. 19. That may make it easier to find these planets, but it also makes the sky brighter around them and diminishes the contrast.

Daylight saving time ended Nov. 1. This will be a 25-hour Sunday right after Halloween. Clocks are reset to one hour earlier. If you forget to change your clocks, at worst you’ll be one hour early to meetings, appointments or family gatherings. Bring a book.

(A bill working its way through the Legislature at first sought to eliminate daylight saving time in Alaska, and with a recent amendment now seeks to change Alaska to multiple time zones. It’s currently in the Senate Finance Committee.)

For astronomy, the end of daylight saving time means the sky gets dark one hour earlier, from around 7 p.m. Oct 31 to 6 p.m. to Nov. 1.

Looking at the sky around 11 p.m., prominent constellations and stars are the Big Dipper (part of Ursa Major) high in the northeast and the Little Dipper high in the north. The three stars of the summer triangle — Cygnus with Deneb, Lyra with Vega and Aquila with Altair, are now low in the northwest. It’s perhaps comforting that in Alaska we can see this summer triangle all winter along, albeit near the horizon.

Cassiopeia appears overhead, in the zenith, and Pegasus’ square/diamond is in the southwest.

In the east, Gemini with Castor and Pollux, Cancer with the Beehive cluster and Leo have risen, following Orion with red Betelgeuse and blue Rigel, which are now high in the southeast (that’s why I chose the late evening for my description). Auriga with Capella and Taurus with Aldebaran, the Pleiades star cluster, currently with the very bright Jupiter, are now high in the south.

Neptune and Uranus are relatively high in the south in Aquarius and Pisces (both are below Pegasus). A good finder chart is needed, though. Try here. The first quarter moon joins Neptune on Nov. 19, and the almost-full moon joins Uranus on Nov. 21 and 22. That may make it easier to find them, but it also makes the sky brighter and diminishes the contrast.

Wait for the bright planets until morning. The spectacle that started last month continues — before dawn you can see very, very bright Venus, very bright Jupiter and fainter reddish Mars lined up, about to leave the constellation Leo and enter Virgo. They all rise in the East around 2 a.m.

Venus passed Jupiter on Oct. 25 and passes Mars on Nov. 2. The crescent moon joins Jupiter on Nov. 6 and Mars and Venus on Nov. 7. To their right (farther in the south) are bright stars Procyon and Sirius and the winter constellations Orion and Taurus. They are not yet prominent in the evening sky because it’s not winter yet.

Just to the right of the three planets is Leo’s Regulus, which is about as bright as Mars. To the left, farther in the northeast, appears the red giant Arcturus. If you observe nightly you can see how they move (a combination of their own orbit and of Earth orbiting, as well) — Venus passes Mars and recedes from it since it orbits faster, and Mars recedes from Jupiter as it orbits faster. The diagram shows how the planets move in front of the background stars. On the left are stars in Virgo, on the right in Leo. So the star near Venus in mid-October is the blue giant Rho Leonis, which is 20 times more massive than our sun and four times as hot.

On its way to Jupiter, sunlight has to traverse eight times the distance compared to Venus, thus the amount of sunlight is reduced to 1/64. Jupiter is 12 times larger in diameter —144 times in surface area — thus reflects that much more of what is left of sunlight at its distance than Venus. That reflected sunlight traverses nine times the distance to Earth, compared to Venus again, so it’s reduced to another 1/81. The outcome is we get 30 to 40 times more reflected sunlight from Venus than from Jupiter. Therefore, the Morning Star appears much brighter than the Giant Planet. Continue reading →

Compared to September, the constellations in the October night sky have shifted toward the east. Bootes sets in the northeast, with its brightest star, Arcturus, seen in the early evening on the northeastern horizon.

Prominent constellations and stars this month are the Big Dipper (part of Ursa Major) low in the north, and the Little Dipper (part of Ursa Minor) high in the north. Cygnus with Deneb, Lyra with Vega and Aquila with Altair are still high in the west. These three stars form the summer triangle. It’s perhaps comforting that in Alaska we can see this summer triangle all winter along, even if only on the horizon.

Cassiopeia appears overhead, near the zenith, and Pegasus’ square/diamond is high in the south. Very late in the evening, Orion rises with Betelgeuse and Rigel in the east, following Taurus with Aldebaran and the Pleiades star cluster.

It still seems that the planets are hiding from our view. At least in the evening, no bright planets appear. Still, try to observe Neptune and Uranus, which appear relatively high in the south, in Aquarius and Pisces (both are below Pegasus). A good finder chart is needed, though. Try http://www.skyandtelescope.com/wp-content/uploads/WEB_UrNep_Finders.pdf.

The almost-full moon joins Neptune on Oct 22, and the full moon joins Uranus on Oct, 25. The moon may make it easier to locate them, but it also makes the sky brighter and diminishes the contrast.

While Saturn is a fair distance from our sun, it is also in the constellation of Scorpius, which is very low on the horizon in Alaska, so it can’t be observed this month.

We had a great summer with many sunny and warm days, probably not taking a look at the one star that was visible almost every day. That’s a good thing, because at a distance of only 94.5 million miles, it so close that it is just too bright — our sun.

Now that nighttime has increased appreciably, a lot more stars can be seen and safely viewed. They’re much farther than our sun, at distances of 50 trillion miles and more, so they appear as small and more or less faint (or bright) points of light when compared with the sun.

During late evenings last month some prominent bright stars, such as Arcturus, Vega, Deneb and Altair, were already visible. Now it’s easy to find constellations, such as the Big Dipper low in the northwest. Take the distance between the Big Dipper’s last two stars and extend it five times towards the zenith (the point straight up) and you get to Polaris, the North Star, which is a semibright star at the end of the Little Dipper’s handle. It also marks our latitude on the Kenai Peninsula at 60 degrees above the northern horizon.

Next, find the constellation Cassiopeia, in the shape of a W, on the other side of the Little Dipper, high in the northeast. High in the sky, as well, almost in the zenith, is Cygnus, the swan (it also looks like a cross). Its brightest star, Deneb, connects with two other bright stars, Vega and Altair, in the constellations Lyra, the harp, and Aquila, the eagle. Together they make up the prominent summer triangle.

Just left of that is the Great Square of Pegasus, high in the southeast. Turning to the west we can see bright red Arcturus setting, a sign that summer is over. It can also be found by following the Big Dipper’s handle’s arc.